Distance-instrument



.NO Model.) J OWYER DISTANCE INSTRUMENT.

No. 364,630. Patsntedfiune 14-, 1887.

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n STATES PATENT Urine-a.

OSXVIN \V. LO\VRY, OF DETROIT, MICHIGAN.

DISTANCE-INSTRUMENT.

SPECIFICATION formingpart of Letters Patent No. 364,630, dated Junel l,1887.

Application filed August 90, iPiG.

Serial No. 21!, 101; (No model.)

ToaZZ u-hom it may concern: i

Be it known that LJOHN iii. BOWYEInU. S. N., of Erie, in the countyofErie and State of Pennsylvania, have invented new and usefulImprovcnients in Distance-lnstruments; and I do hereb l :clare that thefollowingisafull, clear, and exact description thereof, reference beinghad to the accompanying d rawi ugs, which form a part of thisspecification.

This invention relates to new and useful iniprovements indistance-instrnments of that class wherein the distance of an object isdet rmined by the angles formed by it with a base-line at two differentstations; and the ineipal object of my invention is to devise 1; use onboard ship to determine its distance while sailing from any stationaryobject on shore, such as light-houses, thereby enabling the mariner toeasily locate the position of his ship on the chartby the use of thisdistance and. the angle of observation.

My inventionconsists in the peculiar construction of the instrument, allas hereinafterdescribed, and set forth in the claims.

In the drawings which accompany this specification, l ignre 1 isaperspective view listance-iustrument. Fig. 2 is a cross- -ion on theline x so in Fig. 1. Fig. 3 is a diagram showing its application.

A is a slotted base-plate carrying two disks, P C, the former beingstationary and the other 'dingly secured thereon, the slot in thebaseate engaging with a tonon on the movable for the purpose of guidingsaid disk on the base-plate.

D and. E are two legs pivotaliy secured at 0 end in the center of thedisks l3 0, res -ectively, by means of the tightening-screws F. The legsD E and the base A are graduated alike and numbered to facilitate thereading. 0 the base-plate the numbers run from the staionary disk towardthe movable disk, zero correspondin with the center of the stationarydisk, and to permit reading from either side the basepiate has twoseries of graduations wit-.1 the numbers marked the reverse in relationto each other. Thenunibering of the graduations on each leg begins atthe pivotal point and runs toward the point. The graduation ispreferably in inches and usual subinstrument of this kind especiallyadapted divisions, which, in theoperation of the in strunient, areintended to represent miles and fractions thereof.

The disks B O are graduated to indicate degrees or points, and themovable disk is provided with two openings, G, by means of which thedistance of the center of the movable disk from the center of thestationary disk may be accurately read on either graduation of thebase-plate.

Suitable sights, H H, may be placed near the free ends of the legs, andalso at their pivotal points, if desired, as it is necessary in theoperation of the instrument to adjust the inner or graduated edge of thelegs in line with the ob jest the distance 'of which it is desircdtofind.

To permit the disk U to approach tiiedi'sk' B as near as possible, thedisks are made to overlap cach-other.

inpractice the instrument is placed on the ship on top of a rail orother suitable elevation, where it can be secured in thelongitudinaldirection of the ship and command a free view for sighting objects. Now,supposing the ship, while sailing on its prescribed course, has sighteda light-house, L, from which its distance is desired to be found, theoperator takes his first. observation by sighting the leg on thestationarydisk in line with the object, and then clamps it firmly inposition by means of the pivotal screw F. Au interval oftinie is nowpermitted to intervene before proceeding with the operation, the shipbeing kept meanwhile on astraight course, which is carefully noted,together with the distancein miles the ship is making since the time ofthe first observation. Suppose an hour has elapsed, in which the shiphas sailed, as indicated by a log, the dis tance 0, equal to fourteenmiles, the operator then adjusts the movable disk Q on the baseplate Ato the graduation-mark 1i, and then, after sighting the leg on themovable disk in line with the light-house, tightens the screw F on thepivotal point of theleg. Now the operation is completed, and thedistances MN from the lighthouse to the first and to the second point ofobservation are directly indicated in miles by the scales on therespective legs at the point of intersection P. v

If the course of the ship during the observation has been noted and theangles of obser I CK vation are read on on the disks, all the factorsnecessary to lay down the course of the ship on a chart are known. Ifthe latter object is the principal aim sought, the graphical executionon the chart is greatly facilitated by the use of asimilar instrument totheone described,

. on which the scales correspondwith the scale on which the map isdrawn, the manner of using such second instrument being self-evident.

My improved instrument is based on the well-known relation ofproportional triangles,

and it will easily be seen that by the use of my instrument on boardship, which permits the .convenient use of a long base-line,1noreaccuratti -esults may be obtained than by the usual means at presentemployed, While at the same time its operation is so simple that its usedoes not require any special training, but can be put in the hands ofany sailor.

My instrument may be also used on land to I advantage whenever the useof a long baselineis at all convenient or made necessary by othercircumstances.

I preferably cover all or portions of the legs with luminous paint topermit sighting an'object in the. dark; but such paint may be used tionof the slotted base A, graduated upon both sides of said slot, thegraduated stationary disk B, the graduated sliding disk 0, having atenon engaging into the slot ofthe base A, the graduat-ed'legs D E;pivotally secured to the center of the disks B C, respectively, and theclamp-screws F, all substantially as described.

3. The combination, with the base A,'having central longitudinal slotand graduated upon each side of said slot, of the graduated disk 0,movable upon said base and provided with two openings, G, substantiallyas described, and for the purpose specified.

JOHN M. BOWYER. Witnesses:

HAL M. Honens, H. S. SPRAGUE.

